Hide and seek, lepidoptera style

Bugs are amazing, they out do so many other species in their ability to adapt and have a huge impact in human existence. They can be largely beneficial of tremendously harmful, but what happens when we have a large impact on them? When we as a society change their habitat? We accelerate extinction and alter their security and ecology.

But one species did take our negative impact and evolved to a more singular suitable colour, rapidly.

 

The peppered moth in Brittan has a famous story behind it and has even had an evolutionary theory designed around its particular adaptation. During the latter half of the nineteenth century, the industrial revolution boomed in England and caused mass amounts of pollution to be pumped into the skies. As the soot covered the trees of nearby forests, it also killed the lichens covering the trees over hundreds of acres of forests. The insects that were morphologically adapted to these habitats suddenly became very visible making them easy prey for predators.

The report I looked into is about explaining the peppered moth’s evolution and doubting some of the scrutiny against this evolutionary idea. They examined the areas on the trees the moths rested and how the different species of lichens on the trees reacted to the pollution and what effect this had on prey. And also the predators and their “bird’s eye view” of the different visibilities of the moths.

The peppered moth theory in evolution works as a way to describe the role of natural selection pressures of predators on prey. This works on how the prey species is able to adapt to become more camouflaged in an ever changing environment. The reason this drastic change in species aspect is so important is because it happed so rapidly when they had a large natural selection pressure against them.The light coloured moths were mostly caught and the shift was towards the dark morphs. This caused directional natural selection:

 

This worked well as an easy way to explain natural selection, but there was still the idea that the moths rarely rested on the trunks during the day, and instead up in the canopy and branches. This was later found true due to their behaviour, but when lichens were more present, they also hung out on the trunks.

The moth species Biston betularia is a species of moth that has a varying morphological structure. The species has a dominant allele for a dark coloured body, while the recessive produces speckled white bodied moths. These are called “morphs” and are varied in there type. The report looks at the two drastic types that were the bases of the study. The dark carbonaria (the dark moth) and typical (the light coloured moth).when the pollution changed the trees black and killed off all the lichens, the white coloured morph was readily picked off the trees and were decreased from there originally high abundance. As the darker moths are easily hidden, the flourished with the new camouflage and increased in numbers.

 

Dark moth morphs (carbonaria) and the white (typical)

So to assess the visibility theory of the species to predators, a measurement was made to look at the different visibilities of the moths with the different background habitats. They then compared the view of human eyes, compared to the inferred views of predator birds.

They found in there research that areas of habitat with no lichen camouflage, the light coloured moths were easily seen on this plain canvas. But as the lichens mottled colour itself reflected UV light, this assumes that when the lichens are present, they are able to hide the moths.

With temporal and spatial changes occurring in their environment, the soot and pollution has since been cleaned up and the lichens are starting recolonization of the forests. They are starting to repopulate on the newest trunks and branches that aren’t as polluted first, with the older trunks being last.

So, as it stands. Even if we change the habitat so drastically that total habitat morphology is altered, it’s reassuring that species are able to select their safest feature to survive this.

This report showed that there i s in fact a way for a trait to be rapidly selected for if they are able to out survive predation through camouflage to their surrounding environment.

I think there’s always been something about moths that have always interested me. I have always been scared of the dark (but luckily have sort of grown past that) but i have constantly had an aspiration for an insect that is only active at night then during the day plays a form of hide and seek against trees- hoping for the best. There not so up themselves I reckon with the wing and body colours. They use their scales to make natural patterns, creating such amazing camouflage, and are now shown to be able to adapt in to their environment rapidly.

 

Here is a link to the report:

http://onlinelibrary.wiley.com/doi/10.1046/j.1420-9101.2000.00170.x/pdf 

 

Its big,sceary, can even bite and gave me nightmares up until now....

To explain my fare of them spinney, creepy, really big bad flying insects  commonly known as the the Huhu beetles, I need you to picture that moment in lord of the rings, Gandalf the grey is having a lonely holiday on top of one of that bad guys towers…. So as you do, he’s just sitting there, chilln, because he carnet exactly go anywhere and he’s bit down in the dumps because his mates going to chop all the trees down.

 Then, out of no were, a large native moth appears. It fly’s right up to him and he snatches it in his hand and holds it like it’s in a cage.

(If your stuck, goes a little bit like this http://www.youtube.com/watch?v=zGBwcfSIugE )

But now imagine….

A little help less up and coming ecologist with no fears being out in the paddock at night. There she was, vulnerable and unaware waiting on the quad bike with the lights on, waiting as her dad opens the gate and moves the electric fence….

Feeling in the moment as she sore what looked like a moth like bug fly up by the lights heading straight towards her. After watching lord of the rings countless times and feeling in the moment, she reached out and snatch’s it from the air…..

Little do you realise though it was not in fact a cute and cuddly soft moth, but instead a very annoyed Huhu beetle that was rudely interrupted mid flight by a nerdy blonde kid.  

And there it was! Clinging hard onto her little hand with its spiny legs and biting mouth parts ready to lash out as she tried to shake it off. It was of chores not having a bar of this rollercoaster she was putting it through and instead took off again in flight. But in the rush of things and still being slightly disorientated crashed straight into her neck. Instantly getting caught up in a mop of blonde hair and now deafened by a very girly scream.

Both of our nights were defiantly not getting better. In fact, I’m not sure about the bug, but that night stayed with me for quiet sometime.

So there you have it. I discovered early in life that night that I’m defiantly not a wizard. And even if so, I still defiantly don’t have any skills at picking my different insects in the pith dark… Or when identifying any as it is. So since this fateful night the Huhu beetle has always given me the creepiest hebigebys. They were everywhere growing up as a wee kid as we live surrounded in native forest. They always managed to find their way into my room at night if I ever left the light on too long, or all over the floor in the garage when dads working late.

So from here on I want to instead talk about the amazing life style of these wee cuddly beetles so we, mostly me, can learn to appreciate them.

And no, not just as food........................................................................................................

> YUM YUM, looks good.....................................................................................................Nah,dont go there. Honestly isnt that great (;

So from this the paper I chose to cover gave a good over view of many different general aspects of the New Zealand Native Huhu grub and beetle life stages, Prionoplus reticularis. It was conducted in the 60’s as our entire forests flora and fauna was first starting to be examined and observed more closely.

The huhu occurs throughout New Zealands main land’s but is not found in any of our small off shore islands.  Naturally before European settlement occurred, the huhu grub was associated with Podocarp and kauri forests, living in the dead decaying wood that was strewn across the forest floors. But as the introduction of Pinus radiate occurred, the grubs soon found these more appealing and they are now easily found in damp logs with a diameter greater than 7-10cm.

 

 

There adult life span in this time only lasts for about 2 weeks were the do not feed. At night they actively fly around the forests and are occasionally distracted by house hold lights. Daylight hours are spent hidden in debris or in bits of bark and if disturbed, will seldom fly to get away. The adult beetle is a nocturnal flyer through warmer and dryer parts of the year between spring and early autumn.  After daylight has passed and it’s now time to start moving around in the dark, they first must warm up. To do so involves walking first for a long period of time. After do so, only then will they think to start to stretch out there wings and fly away. The first flights are usually seldom good attempts and the either land only a few feet away or fall to the ground and overturn, with males doing the most flying. They then become successfully stronger between 15-30mins, this is usually around 10.30-11pm and the only start to decrease in flight around 4am.

(When thinking further on their flight behaviour, the way they take off so slowly and hide in ground burrows. They must be great little snacks for predators such as rats, hedgehogs and ferrits).  The report mentions its natural predator being the Morepork owl with introduced species being the magpie and also the hedgehog.  

The little sweet Huhu beetles it turns out aren’t just out to attack people, they also have their own combats for territory and have ways to fend off such attackers…of any kind. They haves tough mandibles that are able to grasp and hold onto firmly anything that is in close proximity. Battles with other males for territory or copulation rights may last for to as long as 40seconds. In this time it is common to find that an individual has been caused bodily harm, with the loss of palpi, tarsi and antennae frequently lost. Then, often the loser of the fight fly’s away to find a safer more friendly place.  After the copulation with various males, the female can also lay between 24-398 eggs. Not all these survive as their nests in old bits of wood are always disturbed by human activity.

So concluded the research into the fear full little beetle which has always daunted me…

I have learnt to accept were they are coming from as a species. They now days (or nights) not only have one big owl chasing them each night, but add on top of this a ground predator hedgehog and an auzy after a cheap and easy snack. Typical.  And as I’m growing more myself as a budding young entomonologist, I am really finding more and more that i appreciate all the little bugs that we share our daily life next to, even the spiny hairy and bad flight ones. Even back in the 60s they weren’t worried about these wee fullers. Guess we best toughen up our ways! And as my dad says when I still occasionally gauk at a bug “Oh geez, what’s wrong? It won’t eat much” and the classic, “I bet it’s more afraid of you than you are of it.” Wisely put.

But as we need to know, we are still in fact intruders in their own ecological world that they have evolved in and they have adapted to. This amazing accomplishment in its self shows we should defiantly have respect for these magnificent creatures no matter how big or spinney.

Hands down,

I will always be a bug lover!

 

Peace.

(Heres the link: http://rsnz.natlib.govt.nz/volume/rsnz_88/rsnz_88_04_008450.pdf. Enjoy!)

 

Silk thread hunting trap - Sir David Attenborough's Life in the Undergro...

Here is a small clip done by SIR DAVID ATTENBROUGH himself in New Zealand at the waitomo caves!
http://www.youtube.com/watch?v=zHM02ptBGB0

Twinkle Twinkle little star, how i wonder what you are....

When stepping into a cave that’s fully enclosed, cold, damp and you are not allowed to use torches or talk can be quiet discouraging of why you have been dragged into this in the first place (most likely by your weird adventurer or ecological friend…Cough). But once you get a chance to look around once you have stopped the toe stubbing walk down and your eyes have adjusted to the darkness; you see them.There are little stars everwhere. All over the roof, way up the banks and even all over the wall right next to you on the track. Just like little blue/green LEDs that take your breath away, who ever knew bugs could be so pretty? (=

The research paper i chose to discuss talks in an overall review of all of the aspects of the New Zealand species of Glowworm, Arachnocampa luminosa. As the method of prey capture interests me most as it is so unique and its main feature, I will talk in depth more about this and the general habitat and life cycles.

Glowworms are found to prefer the dark and damp habitats found commonly in caves, but they are able to survive on damp covered banks in dense forests areas. They are able to tolerate a wide range of temperature ranges and are only really affected by a change in relative humidity. It is estimated that the Glowworms and the mucus covered threads will dry out at a relative humidity of bellow 90-95%.

As the larvae stage is the longest lived stage of the Glowworm, lasting up to a year, it needs to gain a continuous sufficient amount of prey for its nutrients. The larva lives in a small transperant tube nest  that is suspendd from the roof of the cave and is roughly 2.5 times the length of its own body. New Zealand Glowworms are unlike most other species found overseas, the New Zealand/Australia species is strictly carnivorous feeding on mostly flying insects such as Diptra species and other aquatic insects.

There are considerable differences in the species consumed between the glowworms that live in the forest banks and in the caves, it also varies between summer and winter seasons. It catches its prey by producing numerous long silk “fishing line like” structures that dangle from its nest, covered in its own sticky mucus as glue. It creates these by using its mucus gland which is located in its mouth. The thread is made up of a continuous strand of droplets and the length is gauged not only by the age of the larvae, but the amount of air movement present. Extreme lengths of strands in quiet places can be from 1-50cm. The light that shins out the back end of the larvae through a chemical reaction produces an in vivo blue-green light that attracts insects which then get caught up in the lines. Insects naturally fly upwards towards a light source as it indicates an open space i.e. the night sky. Once caught, the movement of the live insect on the line triggers the Glowworm to move to the thread and retrieve its food. Both touch and chemoreceptors aid in the detection of its prey. As the prey moves more they are caught up in the line and the glow worm slims its way down the thread and pulls it up to feed on the insect. As it now has successfully caught it prey, it turns off its “light to save energy”.

 Once the larva has reached a length of 30-40mm in length it will crawl to find a free dark area to pupate, sometimes travailing up to several meters at a time. The trigger to move into the next stage of life from a larva to become a breeding adult is its body weight and/or size, not being influenced by a change in season or environmental condition.

 Once an adult, they have degenerate mouth parts and do not feed but instead only live for a couple days. In this time they have to find a mate and reproduce if they want to insure their genes are passed onto the next generation. As the adults are very poor fliers, they sometimes by misfortune get caught up in the larva fishing lines, thus getting then eaten by the other larva becoming cannibals.

 

The Male (left) and female (right) New Zealand A. luminosa adults.

 The eye sight of the larvae and the adults are functional on a green UV base line and have very large eyes.

An interesting fact is that Glowworms are found to be more tolerant of high CO2 emissions. With this in mind, and there ability to not be controlled by seasons, they would not have an inital effect on the current climate change issues.

And if you would like to check out the report yourself, here's the direct link:

http://onlinelibrary.wiley.com.ezproxy.lincoln.ac.nz/doi/10.1002/bio.955/pdf

Cheers for reading!!!!!!!!!

I hope you enjoyed my blog!!!

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